ajrothm

I am just curious about this because it seems like a see a LOT more builds with LS2s/LS3s making WELL into the mid 600s and even a few 700ish all with stock bottom ends/heads/bolts etc..... Where as I know the "typical" safe limit for an LS1/LS6 is around 600ish rwhp...

I just always assumed all LS1s/LS6s/LS2s/LS3s used PM rods and cast/hyper pistons so I would think the HP limits would be the same but.....

Am I wrong in this? Is there something inherently stronger in the LS2s/LS3s?

I know all of them are a gamble over 550rwhp or so but...It just seems like the LS2/LS3 guys are able to boost them into the mid 650-700 range relatively safely and from what I read that is taboo on a LS1/LS6 for long term use..

Thoughts?

Z06wanted

People and tuners keep pushing the envelope farther and farther. Used to be the limit was 500rwh and now seems 600rwh and more. To my knowledge no difference. Still cast crank, hypereutectic piston and powered metal rods.

ajrothm

Yeah thats what I figured... It just seems like (reading the C6 Fi section) that people with LS2/3s are making 700rwhp pretty regularly on stock motors(aside from blower cams)... I found a few threads of them popping but....seems like quite a few are living...

I fully understand HOW the LS2s/3s are making that much more power (bigger displacement, square port heads/intakes etc etc)... I am just curious WHY/HOW they are holding up?

I KNOW a lot has to do with the tuning/detonation prevention etc etc..... But I am wondering if maybe these cars are not being ran hard that often or something or what..... ?

I am pretty comfortable with mine in the 600rwhp level for safety, I would be quite nervous dumping another 4-5 psi into it and adding another 100rwhp on the stock engine...Sure it may live on the dyno but....Would I trust it at the strip or hammering it on the street a couple hundred miles from home? Probably not... I'm not rushing out to try to blow up my 26k mile all stock engine but I am curious what the consensus is to why the LS2/3s can hold 100rwhp more then my LS6....

Really more food for thought really... I won't be cranking mine up any higher until i have loot to do a forged bottom and fuel system etc...

robert miller

LS2 block for sure is the best block to get your boost cars to stay together, This ls2 block better than the LS3 block due to the bore of the block. Robert

regorih

Don't forget the fact that the LS2/3 engines are fresh with low milage and less wear and tear. I also like to think that the newer engines are receiving the benefit of all the past experiences that tuner have learned over the years with blowers, fuel systems, and the fuel it's self such as meth injection and E85.

mdaniel

There is also the fact that you generally don't hear when people blow up. Like gambling - people only tell you about their wins.

9lives

The Ls2 bottom end is stronger. if you compare the ls1 rods vs the ls2's you will see the difference.

ajrothm

Interesting...

Any difference in LS6 rods from LS1s?

I am thinking for my future build I will use my original LS6 block and crank and just put killer rods/pistons in it......Keep my original 243 heads, maybe have them ported and put stainless valves in them so they can handle more boost....Keep it relatively simple and cost effective... I'll probably have HKE build it since I am local to him..... I would like to make an honest/reliable 750rwhp...

Its just crazy when you see stock LS2s/LS3s making that kind of power on stock motors...

9lives

You can make 750 on a ls6 block and crank but you do have to change rods and pistons. HKE is awesome i went there to buy my ls2 rods and pistons for my 6.0 lq4 they have tons laying around. I just finished my build but i havent tuned it. I havent had a chance to take apart a ls6 so i cant tell you first hand if they are beefier. You can get a Junkyard 5.3 stock with a big turbo and get 700 easy.

Milan

LS2 also has little things that are better like the timing chain...

CancerJCC

I've thought the same about LS6 v. LS1. Of course this is probably just wishful thinking! I'd love to read some legit comparison between the two as far as durability beside just the less miles, more tuning knowledge etc.

trophystock

The old "you can only make XXX hp with a stock block" is normally from people who have no first hand experience. I know I have tuned allot of LS1 cars that make 700 at the tire and have lived/been living for years. As long as you are careful with the tune and treat it right and don't over spin it . I am also convinced that the centrifugal blowers are easier on the motors then the roots style/turbo cars are. The roots cars make so much bottom end boost so quickly the cylinder pressures must be incredible.
C.W.Barber
V8muscle.net

95wht6spd

Plus being able to make the same power w less boost and RPM due to the larger CID will help some.

mdaniel

Turbos don't have as much parasitic loss. I upgraded to a forged motor to prevent a catastrophic type event where you drive over your own oil going down the track and get killed careening into the wall.

NemesisC5

My plan was to use a combination of parts that would optimize the engines ability to make the most hp/tq possible with the small S-Trim from A&A's first generation Vortech kits. Incrementally, I reached the 700/rwhp mark with meth and a good tune. The old saying still applies, "it's the combination of parts with a great tune".....and some good luck helps too.

trophystock

That has allot to do with it to. Some people really take car of there cars and do not have issues, some people are idiots and tear up anything they own. It is just in there nature.

0C_Williams@RPM

in terms of strength...

Cranks are the same
Pistons are the same
Rods are improved in the LS2-LS3 - BUT the ROD BOLTS STILL SUCK

jobberone

I think the LS1/6 block will reasonably take up to 18lbs for street use although I wouldn't beat on it with that much boost all the time. The LS2 will take a little more low to mid 20s if you're in to doing that sort of thing. Of course if you're boosting that much then you should consider aftermarket heads, studs yada. That's the biggest difference IMO. The LS2 is just a bigger meatier block. Crank is good to about 1000 in both. You should be thinking forged for the rest anyway.

IMO if you have a C5 then stay with the LS1 unless you're going after more than 700-800. If you're going to pound on the car you should build accordingly.

If you're talking about 700 on a stock motor then it really doesn't matter. Both worlds are a little risky at those levels. The block doesn't really matter as much.

Shady

Why would the ls2/3's take more boost than ls1/6's? More cubes at the same boost should net you more power all other things being equal. Also if the blocks are physically the same except for bores and sensor locations (I think) so what makes for the difference in strength? I could be wrong so if I am someone who really knows please chime in...

user_name

Most of everything has been covered in here. For maxing out a stock shortblock the nod goes to the gen4 shortblocks in the 700-800rwhp range.

It really doesn't matter too much in the end, b/c they both have the same weakest point at those levels. The ring gap is too tight, and the ring lands get smashed under the cylinder pressure made at those levels.

I made 750rwhp on my ls6 for years. When it started smoking a little it came out. Pistons looked perfect. It hasn't been torn down yet, but I am sure it was the rings.

Where it gets interesting is the fact that those ring gaps vary from 1 factory engine to another. Most people popping these motors are doing it b/c of the tune or fuel being off, but some people just have bad luck I think, and the rings get smashed.